Automatic cut-off or regulator for gang-boilers



{No Model.) W. U. PAIRBAIRN' 2 Sheets-Sheen 1.

AUTOMATIC GUT-OFF OR REGULATOR FOR GANG BOILERS. No. 394,257. Patented Dec. 1 1888.

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W. U. PAIRBAIRN.

AUTOMATIC GUT-OFF-OR REGULATOR FOR GANG BOILERS. No. 394,257. Patented Dec. '11, 1888.

N. PETERS. Fmuuun m Wnhingtun. n. c.

UNITED STATES PATENT ()FFICE.

XVILLIAM U. FAIRBAIRN, OF HYDE PARK, MASSACHUSETTS.

AUTOMATIC CUT-OFF OR REGULATOR FOR GANG-BOILERS.

SPECIFICATION forming part of Letters Patent No. 394,257, dated. December 11, 1888.

Application filed A ril 25, 1888. Serial No. 271,790. (No model.)

To all whom it may concern.-

Be it known that I, \VI'LLIAM U. FAIRBAIRN, of Hyde Park, in the county of Norfolk and State of Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Automatic (fut-Offs or Regulators for Gang-Boilers, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this speciihiation, in explaining its nature, in which Figure 1 is a view principally in end elevation of a gang of boilers provided with my invention, a portion of one boiler and some of its connections being broken out to better illustrate the same. Fig. 2 is aview in front elevation of a gang of boilers furnished with my invention. 3 is a detail view illustrating the automatic regulator of one of the boilers, and Fig. 4 is a view in plan of a gang of boilers having the features of my invention.

My invention relates to means for auton'iatically governing or regulating the combustion or fire in each furnace of a gang of boilers independently of all the other furnaces of the gang, and also to the automatic regulation of the quantity of steam furnished or provided by each boiler, so that each boiler of the gang shall be connected with the common reservoir or steam-drum only when the boiler-pressure is at or above the average of the pressure of the steam-drum, and so that any boiler or boilers of the gang not supplying steam are cut out automatically until they can supply steam of the required pressure. Heretofore it has been customary to connect all the boilers of a gang with a common steam reservoir or drum and to automatically control the fires of all the furnaces by one automatic regulator placed in the uptake. This construction is defective, in that it does not provide for the proper regulation of each f urnace-fire independently of all the others and does not cut out a boiler which is not making steam of a given pressure from the system or gang, and the steam is at liberty to fiow freely not only to the steam drum or reservoir, but from one boiler to another, and even if a separate damper-regulator were used in connection with each furnace, still, unless there is provision for the automatic cutting out of a boiler not producing steam of the desired pressure, the result is not desirable, because the steam-pressure is equalized throughout all the boilers of the gang as well as in the steam-drum, and consequently each damperregulator, instead of being regulated by the pressure of its boiler, is regulated by the pressure of another boiler or boilers or of all the boilers, and consequently bears no practical relation to the particular furnace-fire which it is desired to control. Not only, therefore, is the use of the automatic damperregulator largely nugatory, but a weakness in one boiler is a weakness of the whole system, in that one boiler, if weak, is subjected to all the pressure and strain of the stronger boilers, and in case of an explosion the result is very much more serious than if the other boiler could be automatically cut out upon a decrease of its own pressure.

I have illustrated as one means of carrying my invent-ion into effect the use in connection with each furnace of each boiler of the gang or group of an automatic damper-regulator. Any form of automatic damper-regulator may be used. I have illustrated in the invention the form known as the Clark damper-regulator, which comprises, essentially, a rubber diaphragm contained in a case and connected with a lever attached to the damper in the uptake. The diaphragm is subjected to the pressure of the water of the boiler, the chamber containing the diaphragm being connected by a siphon with the water of the boiler; and in each steanrpipe connecting each boiler with a common steam-drum or steam-reservoir I have placed a check-valve, which is set to be opened by excess of steampressure upon the boiler side of the connection and to close upon the excess of stea1npressure upon the reservoir or drum side of the connection.

Referring to the drawings, in Fig. 2 I have represented a gang of three boilers, A A A Each boiler has a separate furnace, the boiler A having the furnace a, the boiler A having the furnace a, and the boiler A the furnace a and each boiler is connected with a com- IOO mon chimney or smoke-escape passage, 13, by means of an uptake, the boiler 'A having the uptake b, the boiler A the uptake Z), and the boiler A the uptake b Each uptake has an automatic regulating-damper, 0, one only being represented in Fig. 1, and the office of this damper is to automatically open or increase the opening of the uptake as the fire needs brightening and to automatically close or partially close the passage as the fire needs to be reduced in force or intensity, and the damper is thus automatically operated by the variation of pressure in the boiler, an increase in the boiler-pressure over a given degree causing the damper to be turned to close the uptake and a decrease in pressure causing the damper to be turned to open it. v

The mechanism by which the pressure of the boiler is utilized, as illustrated in the drawings, embodies a case, (1, containing a chamber, (1, in which is arranged a yielding diaphragm, (1 which is connected by a spindle, (Z with a lever, (Z connected by an arm, (Z with the spindle d of the damper O. The chamber of the case is connected with the boiler by means of a siphon, (77, which admits to the chamber water under the boiler-pressure, and this pressure is constantly exerted upon the diaphragm. The extent of pressure necessary for operating the lever is varied or adjusted by means of a weight, (Z hung upon the lever. This is a common form of automatic damper-regulator.

From each boiler of the gang there extends a steam-pipe, E, to a common steam drum orclose by pressure from the steam drum of reservoir in excess of the boiler-pressure. If there are two or' more supply-pipes connecting the boilers with a common steam drum or reservoir, then each of the pipes should be provided with a check-valve of this construction and arrangement.

The operation of the invention is as fol lows: The object to be attained is a uniform combustion of the fuel to maintain, as nearly as practicable, a boiler-pressure in each boiler of a given degree, and this operation as a rule is practically maintained-that is, it is the normal operation of the inventionthe fires are maintained in a uniform condition, and the boilers make and deliver steam ata uniform pressure. If, however, the boiler-pressure of any one or more of the gang of boilers becomes reduced belowthe average pressure of the other boiler or boilers, then it is cut off from the other boilers and steam-drum by the automatic closing of the check-valve in the steam connectingpipe or pipes, and this boiler or boilers remain cut out until the pressure has been increased in the boiler or boilers to the required extent, and this cutting out of the boiler immediately causes its automatic damper-regulator to be opened to cause the fire to be started or increased in in tensity, and to thereby increase the steampressure to the desired extent.

The advantages of the invention in the saving of fuel and in the improved operation of the boilers and in point of safety are obvious.

Another advantage arises from the fact that the automatic control of each damperregulator in the manner specified provides a better draft than would otherwise be the case, in that the draft is utilized only for such fires as need brightening, perhaps a single furnace of the group, or perhaps two or more. I also prefer to attach to each boiler of the gang or group, preferably to the device for controlling 7 the damper-regulator, a steam-gage, D, so that the steam-pressure of each boiler of the group shall be indicated.

Having thus fully described my invention, I claim and desire to secure by Letters Patent of the United States 1. The improvement in the steam and fire regulation of a gang of boilers discharging steam into a common drum or reservoir, comprising the combination, with each boiler of a gang or group, of an automatic damper-regulator controlled as to its operation by the steam-pressure of the boiler, and one or more steam-connecting pipes connecting each boiler with a common steam drum or reservoir, and a check-valve located or arranged in each connecting pipe and set to automatically open upon the excess of the boiler-pressure of the boilers, or either of them, as compared with the pressure in the steam drum or reservoir, and to automatically close upon the excess of the steamn'essure of the drum or reservoir as compared with that of the boilers or boiler, substantially as described.

2. The combination of a gang or group of boilers, A A A a separate furnace for each boiler, a separate uptake for each boiler, an individual damper, C, for each uptake automatically operated by a mechanism controlled as to its operation by the pressure of the boiler with which it is used, a common steam I drum or reservoir, and a connecting-pipe, E, for each boiler, and a check-valve, e, in each connecting-pipe set to automatically open upon the excess of the boiler-pressure of the boilers, or either of them, as compared with the pressure in the steam drum or reservoir, and to automatically close upon the excess of the steam-pressure of the drum or reservoir as compared with that of the boilers or boiler, substantially as described.

3. The combination of a gang or group of boilers, A A A a separate furnace for each boiler, a separate uptake for each boiler, an individual damper, O, for each uptake automatically operated by a mechanism controlled as to its operation by the pressure of the boiler with which it is used, a common steam drum or reservoir, and a connecting-pipe, E, for each boiler, and a check-valve, e, in each the gang or group connected directly therewith or with the chamber of the pressurc-reg- 1o ulator, substantially as described.

VILLIAM U. FAIRBAIRN.

In presence of- F. F. RAYMOND, 2d, J. M. DOLAN. 

